Change taxonomy for categories

Hi

I am using this plugin with a directory theme where i have directory listings showing as adverts in a sidebar on specific pages.

The directory listings are in categories but not normal categorys, they are within the themes own categories where the taxonomy is called “ait-dir-item-category”

These are not selectable using your plugin, only the normal categories which are not in use.

I have tried to edit the plugin changing $categories = get_terms( 'category' ); to $categories = get_terms( 'ait-dir-item-category' ); but this had no effect.

I wonder if you could assist me in changing what taxonomy the plugin looks for for the categories please so that I can filter via the theme categories and not the default WP categories.

Thanks.

https://wordpress.org/plugins/recent-posts-widget-extended/